A new water treatment system should not be treated like an appliance that simply appears in the basement and starts working. Before the installer leaves, you should understand what was installed, which water lines it serves, how to operate it and what signs would indicate a problem.
Use this checklist during the final walkthrough. Keep your proposal nearby so you can compare the finished installation with what you agreed to buy.
Confirm what equipment was installed
Ask the installer to identify every tank, housing, valve, cartridge and control. Match the equipment to the written proposal. Model numbers, tank sizes and included components should agree with the paperwork.
If something looks different, ask why before accepting the work. A substitution may be reasonable, but you should receive a clear explanation and updated documentation showing exactly what you own.
Record the model and serial number for each major component. Take clear photos of the equipment labels. These details can make future service calls and replacement part searches much easier.
Trace where the treated water goes
Have the installer show you where the incoming water enters the treatment system and where the treated line returns to the house. Ask which fixtures receive treated water and whether any lines bypass the equipment.
Check outdoor faucets, irrigation lines, kitchen cold water, refrigerator lines, utility sinks and any drinking water faucet separately. Do not assume that every fixture follows the same plumbing path.
If the system includes more than one treatment stage, ask the installer to explain the order of operation. You should know which unit handles sediment, hardness, odor or another stated concern.
Learn the shutoff and bypass controls
Ask the installer to demonstrate the main water shutoff and the system bypass. Then operate the bypass yourself while the installer watches. Labels should be readable, and the valves should be accessible without moving heavy storage or using special tools.
Find out what the bypass actually does. On some installations, bypassing one unit may leave another unit active. If several valves must be moved in a particular order, photograph their normal and bypass positions.
Ask when you should use bypass mode, such as during equipment service or if a leak develops. Also ask whether water remains available to the house while the system is bypassed.
Inspect the installation area
Look around every new plumbing connection for moisture. Run nearby fixtures and inspect again while water is flowing. A dry paper towel pressed around a fitting can reveal a slow seep that is difficult to see.
Make sure tanks stand securely and do not rock. Pipes should be supported rather than placing their weight on a control valve or filter housing. Electrical cords should reach their outlets without being stretched across a walkway or placed where they can get wet.
Confirm that you can remove a filter housing, open a salt tank or reach a service valve without dismantling shelves or moving other equipment. Leave enough working space for routine maintenance and future repairs.
Check the drain arrangement
If any unit regenerates, backwashes or flushes automatically, ask the installer to show you its drain line. Confirm where the discharge goes and how the line is secured.
The drain line should not be kinked, crushed or positioned where it can easily be pulled loose. Ask how an air gap or other backflow protection is provided. Have the installer explain what normal discharge looks and sounds like so you can recognize an overflow or obstruction.
Review the programmed settings
Do not settle for hearing that the system is set automatically. Ask which values were entered and what information was used to select them.
Depending on the equipment, relevant settings may include measured hardness, household capacity, regeneration trigger, backwash duration, filter reminder or clock setting. Ask which settings you may adjust and which should be changed only by a service technician.
If the system has a display or app, confirm that you can read the status, recognize an error and restore basic settings after a power interruption. Write down any access code or account information that belongs to you.
Test fixtures before accepting the work
Run cold water at several treated fixtures and check for steady flow, unusual sputtering and visible particles. Temporary air or discoloration may occur after plumbing work, but the installer should explain what is expected and flush the system as required.
Test hot water too. Existing water in the heater may not reflect the newly treated supply immediately, but hot and cold fixtures should operate normally without leaks or blocked aerators.
Check toilets, showers, washing machine connections, refrigerator dispensers and drinking water faucets if they were affected by the installation. Look under sinks and around appliance connections for leaks.
Ask how performance will be verified
Ask what measurement will confirm that the system is doing its intended job. The answer should connect directly to the problem the equipment was sold to address.
For a softener, that may involve checking untreated and treated hardness. For a contaminant reduction system, it may require an appropriate follow-up test and a defined sampling location. Taste alone is not a reliable performance check for every water concern.
Request copies of any before and after results. Also ask when another test is appropriate and whether you or the provider is responsible for arranging it.
Clarify routine maintenance
Ask for a simple maintenance schedule tied to your actual equipment. It should state what must be added, cleaned, inspected, tested or replaced.
For each task, confirm:
What part or supply is required, how you can tell service is due, whether you can perform it yourself, what happens if it is delayed and who to contact if the equipment behaves abnormally.
Avoid relying only on a generic reminder interval. Water use and incoming water conditions can affect how quickly some components become exhausted or clogged. Ask whether the system has a meter, alarm, pressure reading or test result that provides a better maintenance signal.
Collect the documents that belong with the system
Before final payment, gather the signed proposal, itemized equipment list, manuals, warranty terms, test results and service contact information. Ask for written confirmation of any promised maintenance visit, labor coverage or follow-up testing.
Keep photos of the completed installation with these records. Include wide photos showing the plumbing layout and close photos showing labels, valve positions and programmed settings.
Know what should trigger a service call
Ask the installer to name the warning signs that matter for your system. Examples can include continuous draining, a sudden pressure drop, water around a tank, repeated error messages, an unusual change in treated water or a unit that cycles at unexpected times.
Get both the normal service number and instructions for handling an active leak. You should know how to stop the water or bypass the equipment without waiting for a return call.
Do a final paperwork check
Compare the completed installation with the proposal one final time. Confirm that optional components, plumbing changes and promised setup work are present. If anything remains unfinished, put the remaining task and responsibility in writing.
If you are still choosing a provider, the rating methodology explains the factors Midwest Water Ratings uses to evaluate companies. Homeowners in the flagship market can also review the St. Louis provider ratings before scheduling estimates.
A good handoff ends with more than running water. You should be able to identify the equipment, operate the bypass, explain the maintenance plan and show a service technician exactly what was installed.